Reduced Dielectric Loss and Strain Hysteresis in Fe and Mn Comodified High-Temperature BiScO3-PbTiO3 Ceramics

There is a growing requirement for high-temperature piezoelectric materials in the petrochemical, automotive, and aerospace industries. Here, the piezoelectric materials of Fe and Mn comodified 0.36BiScO(3)-0.64PbTiO(3) (BS-PTFMn) ceramics with high Curie temperature (T-c), large mechanical quality factor (Q(m)), and reduced strain hysteresis were presented. XRD results revealed that all the BS-PTFMn ceramics have a pure perovskite structure with tetragonal symmetry, and the ratio of c/a is insensitive to the contents of Fe. With the modifications of Fe, the dielectric loss tan and strain hysteresis decrease clearly, while the mechanical quality factor improves significantly. The Curie temperature, piezoelectric constant, planar electromechanical coupling factor, dielectric loss, and mechanical quality factor of the BS-PTFMn with 3% Fe content are 492 degrees C, 235pC/N, 0.38, 0.6%, and 280, respectively. BS-PTFMn ceramics show 50 degrees C higher T-c than BS-PT morphotropic phase boundary composition. The figure of merit (product of Q(m), epsilon(T)(ij) and k(ij)) of BS-PTFMn ceramics is about five times than that of pure BS-PT ceramics. Furthermore, for the BS-PTFMn ceramics with Fe content of 3mol%, the high field strain coefficient d(33)(*) value calculated from the electric-field-induced strain curves (S-max/E-max) is 320pm/V, while the strain hysteresis (under 40kV/cm) is reduced to one fifth that of unmodified BS-PT ceramics. Moreover, the temperature-dependent electromechanical coupling coefficient and dielectric constant are very stable in the temperature range from room temperature (RT) to 450 degrees C. These results indicated that BS-PTFMn ceramics are promising for high-temperature piezoelectric applications.